Scorpion venoms and neurotoxins: An immunological study

Delori, P.; Rietschoten, J. Van; Rochat, Hervé

doi:10.1016/0041-0101(81)90044-1

Cited by 88 publications

(30 citation statements)

References 15 publications

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“…This result confirms previous findings that showed that the antivenom produced by Institute Pasteur of Morocco is able to neutralize almost all venoms of dangerous north African scorpions. 27 To examine the relationship between the severity of scorpion envenoming and serum venom levels, we measured the concentration of venom in serum samples of patients upon hospital admission. The results showed a correlation between the severity of envenoming and serum venom levels.…”

Section: Discussionmentioning

confidence: 99%

Scorpion envenomation and serotherapy in Morocco.

Ghalim

El-Hafny²,

Sebti³

et al. 2000

The American Journal of Tropical Medicine and Hygiene

111

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Abstract.A clinical and biologic study was conducted in Morocco to assess the efficiency of antivenom therapy for treating victims of scorpion stings. Epidemiologic and clinical data were collected from 275 patients envenomed by Androctonus mauretanicus mauretanicus and Buthus occitanus scorpions. Patients received antivenom or other drugs. Blood samples were collected at the time of hospital admission and 1 hr and 3 hr after treatment. Serum venom levels were quantified by using an ELISA. An association was found between clinical signs of envenoming and the level of venom in serum. Patients classified as grade II (moderate envenoming) had higher serum levels of venom level than patients classified as grade I (mild envenoming). At admission to the hospital, the mean venom concentration was not significantly different between the group not treated with antivenom, the group who received 2-5 ml of antivenom, and the group who received 10 ml of antivenom. A significant decrease in serum venom levels and an improvement in the clinical conditions were observed in patients administered 10 ml of antivenom. The lower decrease in serum venom levels in patients who received 2-5 ml of antivenom was due to lower doses of antivenom. No difference in the venom concentration was observed in patients who were not treated with antivenom. The absence of administration of antivenom increased the risk of developing clinical signs at the end of the hospitalization period. However, this risk was much higher when more than 1 hr elapsed between the time of the scorpion sting and the time of hospital admission. The results demonstrate that antivenom is effective in decreasing circulating venom and morbidity. Serotherapy is more efficient when given as soon as possible after envenomation and with adequate quantities of antivenom.In north Africa, as in numerous tropical countries, envenomation by scorpion stings is a major public health problem, particularly in children. [1][2][3][4] The black scorpion (Androctonus mauretanicus mauretanicus) and the yellow scorpion (Buthus occitanus) are the most dangerous scorpions and are responsible for the majority of stings in Morocco. The epidemiologic data are incomplete, but the number of scorpion stings is estimated to be 40,000 per year in Morocco.Scorpion venoms are a complex biochemical mixture containing numerous neurotoxic polypeptides. 5,6 These polypeptides enhance excitability of nerve and muscle cells in scorpion sting victims and also cause death, particularly in children. 7 The onset of clinical symptoms is rapid (within 5-30 min) following the sting. 8,9 Respiratory failure and cardiovascular manifestations are the usual causes of death. 9-11 The toxicity of A. mauretanicus mauretanicus venom is due to the presence of neurotoxins that are specifically active on sodium and potassium channels. 6,12 The severity of scorpion envenoming and the rapid diffusion of inoculated venom require that appropriate treatment be started as soon as possible after the sting. Most investigators consider a...

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Section: Discussionmentioning

confidence: 99%

Scorpion envenomation and serotherapy in Morocco.

Ghalim

El-Hafny²,

Sebti³

et al. 2000

The American Journal of Tropical Medicine and Hygiene

111

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“…Immunological data have shown that the antigenic groups are the same as the structural groups (Delori et al, 1981). Moreover antitoxins only recognize and neutralize toxins that belong to the same group (Delori et al, 1981 ;El Ayeb et al, 1983a).…”

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confidence: 99%

A Recombinant Insect‐Specific α‐Toxin of Buthus occitanus tunetanus Scorpion Confers Protection Against Homologous Mammal Toxins

Bouhaouala‐Zahar

Ducancel

Zenouaki

et al. 1996

European Journal of Biochemistry

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We have constructed a cDNA library from venom glands of the scorpion Buthus occitanus tunetanus and cloned a DNA sequence that encodes an α‐toxin. This clone was efficiently expressed in Escherichia coli as a fusion protein with two Ig‐binding (Z) domains of protein A from Staphylococcus aureus. After CNBr treatment of the fusion protein and HPLC purification, we obtained approximately 1 mg recombinant α‐toxin/I bacterial culture. The toxin, called Bot XIV, displays no toxicity towards mammals but is active towards insects as shown by its paralytic activity against Blatella germanica cockroach and by electrophysiological studies on Periplaneta americana cockroaches. The Bot XIV protein fused to two Z domains is highly immunogenic in mice and induces production of antisera that specifically recognize and neutralize highly toxic components that had been injected into mice. This fusion protein could be very useful for development of potent protective antisera against scorpion venoms.

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“…The principal toxic compounds in scorpion venoms belong to a clearly defined family of homologous proteins, composed of single chain of 63-70 amino acid polypeptides cross-linked by four disulfide bridges (Miranda et al, 1970;Kopeyan et al, 1974;Darbon et al, 1982;Gregoire and Rochat, 1983). These sodium channel neurotoxins have been classified into several structural groups on the basis of primary structure (Rochat et al, 1979;Dufton and Rochat, 1984;Posanni, 1985;Watt and Simard, 1984) and immunological (Delori et al, 1981) criteria. The four first groups (I-IV) reveal a good correlation between amino acid sequences and pharmacological properties and contain the ␣-scorpion toxins active on vertebrates.…”

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confidence: 99%

Scorpion Toxins Affecting Sodium Current Inactivation Bind to Distinct Homologous Receptor Sites on Rat Brain and Insect Sodium Channels

Gordon

Martin‐Eauclaire

Cestèle

et al. 1996

Journal of Biological Chemistry

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187

259

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Sodium channels posses receptor sites for many neurotoxins, of which several groups were shown to inhibit sodium current inactivation. Receptor sites that bind ␣-and ␣-like scorpion toxins are of particular interest since neurotoxin binding at these extracellular regions can affect the inactivation process at intramembranal segments of the channel. We examined, for the first time, the interaction of different scorpion neurotoxins, all affecting sodium current inactivation and toxic to mammals, with ␣-scorpion toxin receptor sites on both mammalian and insect sodium channels. As specific probes for rat and insect sodium channels, we used the radiolabeled ␣-scorpion toxins AaH II and Lqh␣IT, the most active ␣-toxins on mammals and insect, respectively. We demonstrate that the different scorpion toxins may be classified to several groups, according to their in vivo and in vitro activity on mammalian and insect sodium channels. Analysis of competitive binding interaction reveal that each group may occupy a distinct receptor site on sodium channels. The ␣-mammal scorpion toxins and the anti-insect Lqh␣IT bind to homologous but not identical receptor sites on both rat brain and insect sodium channels. Sea anemone toxin ATX II, previously considered to share receptor site 3 with ␣-scorpion toxins, is suggested to bind to a partially overlapping receptor site with both AaH II and Lqh␣IT. Competitive binding interactions with other scorpion toxins suggest the presence of a putative additional receptor site on sodium channels, which may bind a unique group of these scorpion toxins (Bom III and IV), active on both mammals and insects. We suggest the presence of a cluster of receptor sites for scorpion toxins that inhibit sodium current inactivation, which is very similar on insect and rat brain sodium channels, in spite of the structural and pharmacological differences between them. The sea anemone toxin ATX II is also suggested to bind within this cluster.

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Scorpion venoms and neurotoxins: An immunological study

Cited by 88 publications

References 15 publications

Scorpion envenomation and serotherapy in Morocco.

Scorpion envenomation and serotherapy in Morocco.

A Recombinant Insect‐Specific α‐Toxin of Buthus occitanus tunetanus Scorpion Confers Protection Against Homologous Mammal Toxins

Scorpion Toxins Affecting Sodium Current Inactivation Bind to Distinct Homologous Receptor Sites on Rat Brain and Insect Sodium Channels

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